doclets/gtkdoc: Fix ignoring headers. Call gtkdoc-scan on specific headers
doclets/gtkdoc: Fix ignoring headers. Call gtkdoc-scan on specific headers

frida/vala,GNOME/vala,frida/vala,GNOME/vala,GNOME/vala,frida/vala,GNOME/vala,frida/vala,frida/vala